About 40 people gathered at the Mountlake Terrace Senior Center Tuesday night to hear the draft strategy to address invasive plant species growing in Lake Ballinger and choking out native plants and fish.
Located between Edmonds and Mountlake Terrace, Lake Ballinger is bordered by private homes, a City of Mountlake Terrace-owned park and the Nile Golf and Country Club.
During the meeting on Sept. 11, experts examined several options for eliminating non-native species, including manual removal, creating physical barriers and herbicides.
Laura Reed, stormwater program manager for the City of Mountlake Terrace and the project manager for this effort, was the first to speak. Reed introduced Dr. Harry Gibbons, a limnologist from TetraTech, who has 45 years of experience working with local lakes. She also recognized city staff members who were present such as Patrick Johnson, stormwater technician for the City of Edmonds, and Eric LaFrance, Mountlake Terrace public works director.
The invasive aquatic vegetation was brought to Reed’s attention by the Lake Ballinger/McAleer Creek Watershed Forum, which works to addresses problems and improve the lake. The forum is made up elected officials from the cities of Lake Forest Park, Edmonds and Mountlake Terrace, as well as concerned citizens, many of whom were present at the meeting.
Reed said she received a small grant from the Department of Ecology to hire TetraTech to bring scientific expertise to this issue. In addition, a survey has already been done on Hall Lake in Lynnwood and Lake Ballinger to assess the amount of invasive aquatic vegetation. During a couple of steering committee meetings, a draft strategy was created for public input.
The draft plan will be finalized early October and the final plan will be sent to the Department of Ecology in hopes of receiving a grant for the project.
A dense amount of aquatic vegetation is creating low oxygen and high phosphorous in the lake, which is bad for the water and fish.
“One of the things we’re trying to do is protect the benefits and the uses of your lake,” Gibbons said. “That includes both the aquatic habitat and ecosystem, and your recreation and aesthetic values that you have.”
Currently, Lake Ballinger is over-producing vegetation in the littoral zone of the lake. This is the shallow part where most life lives and what is first seen by the public.
“It’s covered by invasive species right now and these invasive species are inhabiting everything,” Gibbons said. “They reduce the water quality, reduce oxygen for other life, prevent fish, boats and humans from moving around because they’re so dense.”
Overall, Lake Ballinger has dense growth. Myriophyllum spicatum, commonly known as Eurasian water milfoil, is the biggest problem, Gibbons said, because it covers the most area and grows deep in the water.
Another invasive plant is Nymphaea, or fragrant water lily, which is filling up the lake and making the lake smaller. The native lilies, Nuphar, or yellow pond lily, are being pushed out by the fragrant water lilies.
Lake Ballinger has a small amount of a native weed, Potamogeton amplifolius, commonly known as large leaf pondweed, that is only growing in the shade where the non-native weeds cannot flourish. Another invasive plant that was found is Potamogeton crispus, or curly leaf pondweed, which is very aggressive because it can reproduce by its roots and its seed. (The Eurasian water milfoil only reproduces in fragments.) The curly leaf pondweed, like the invasive lilies, overproduces algae.
“All around the lake is nothing but plants,” Gibbons said. “There’s no beach. There’s no aquatic diversity of habitat in that littoral zone. It’s stressed and it’s over producing.”
Gibbons went over what the steering committee considered for tackling these invasive plants. One option is manual hand-pulling and raking. While this seems like a good option, raking the Eurasian water milfoil is only going to create more milfoil if you don’t collect it all because it spreads by the fragments. Cutting the fragrant white lily is effective, however.
“Now remember if you cut a plant, you should take it out of the lake because neither Lake Ballinger or Hall Lake need anymore nutrients,” Gibbons said.
The steering committee also considered mechanical harvesting, which involves a machine that cuts the plants. Again, this only spreads more milfoil and is very expensive.
Another option is dredging, which can get the muck and roots out, but it is also very expensive.
Physical bottom barriers, such as placing a burlap tarp weighed down by burlap sandbags, is a viable option because they will cover and kill the plants. Burlap tarps are suggested because burlap biodegrades over time, although rocks can be used instead of sandbags, Gibbons said. There is a permit from Washington Department of Wildlife available online that allows lake residents to cover up to a half acre around their docks. Lake residents can begin to take action against the invasive milfoil and lilies as soon as they print the permit.
The last option is the use of chemicals.
“The intensity of the non-native plants here is so great that we’ve got to really weed back so we can get to other options like the cutting and the bottom barriers,” Gibbons said.
The plan is to use fluridone, which is a less-robust herbicide that will still control the invasive species. This herbicide will not harm the water, swimmers, insects or fish.
“Fluridone inhibits the photosynthetic cycle itself,” Gibbons said. “We’re looking at an integrated, adaptive program that’s a long-term program.”
It must be a slow process to allow the native plants to recover, Gibbons added. It will be intense for up to 12 years, but maintenance will always be needed to ensure the non-native species do not return and outgrow the native species.
Gibbons said it is going to be hard to eradicate the Eurasian water milfoil because boats can carry it in with them, but there is a good chance of getting rid of the fragrant water lily and that there needs to be an aggressive attack on the curly leaf pondweed.
“Let’s get the invasive down by 80 percent so that we have a better habitat and more better fisheries,” Gibbons said.
One citizen asked how nitrogen entering Lake Ballinger can be limited. Gibbons responded that it is part a long-term broad education process, which includes storm water management and adaptive landscaping. One citizen said he and his neighbors vowed to stop fertilizing their lawns.
“Everything we do has an impact on this planet and downstream,” Gibbons said.
There are three target areas for the four-year program. The first area is the public boat launch because to get grant money we must prioritize the public areas, Gibbons said.
The first year of treatment will begin summer 2019. Lake Ballinger is 100 acres and to treat one quarter of the lake — 25 acres — it will cost around $8,000-$12,000, Gibbons said. The cost will be shared by lake residents through their Lake Management District.
— Story and photo by Hannah Horiatis